Details

Autor(en) / Beteiligte

• Kohli, A. (John Innes Centre, Norwich, UK.)
• Leech, M
• Vain, P
• Laurie, D.A
• Christou, P

Titel

Transgene organization in rice engineered through direct DNA transfer supports a two-phase integration mechanism mediated by the establishment of integration hot spots

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 1998-06, Vol.95 (12), p.7203-7208

Ort / Verlag

United States: National Academy of Sciences of the United States of America

Erscheinungsjahr

1998

Quelle

MEDLINE

Beschreibungen/Notizen

• Organization of transgenes in rice transformed through direct DNA transfer strongly suggests a two-phase integration mechanism. In the "preintegration" phase, transforming plasmid molecules (either intact or partial) are spliced together. This gives rise to rearranged transgenic sequences, which upon integration do not contain any interspersed plant genomic sequences. Subsequently, integration of transgenic DNA into the host genome is initiated. Our experiments suggest that the original site of integration acts as a hot spot, facilitating subsequent integration of successive transgenic molecules at the same locus. The resulting transgenic locus may have plant DNA separating the transgenic sequences. Our data indicate that transformation through direct DNA transfer, specifcally particle bombardment, generally results in a single transgenic locus as a result of this two-phase integration mechanism. Transgenic plants generated through such processes may, therefore, be more amenable to breeding programs as the single transgenic locus will be easier to characterize genetically. Results from direct DNA transfer experiments suggest that in the absence of protein factors involved in exogenous DNA transfer through Agrobacterium, the qualitative and/or quantitative efficiency of transformation events is not compromised. Our results cast doubt on the role of Agrobacterium vir genes in the integration process